Method of selectively floating one or more minerals contained in ore pulp



Apnl 28, 1931. M. KRAUT t 1,802,919l

METHOD OF SELECTIVELY FLOATING ONE OR MORE MINERALSCONTAINED IN ORE PULP Filed Feb. 20, 1928 2 Sheets-Sheet l F1' gl In Ven 014.

April 28, 1931. M. KRAUT 1,802,919

METHOD OF SELECTIVELY FLOATING ONE OR MORE MINERALS CONTAINED I-N ORE PULP Filed Feb. 20, 1928 2 Sheets-Sheet 2 Patented Apr. 28, 1931 Partnr orifice MAX KRAUT, OF SAN FRAINGISCO, ALIFQRNIA METHOD'OF SELECTIVELY FLGATING ONE 0R MORE MINERALS GONTAINEB IN GBE FULP Application le February 20, 1928. Serial Elo. 2255.839.

The object and scope of the present invention pertains to the method of promoting and intensifying effects produced in that `field of flotation process known as differential, preff erential or selective flotation. v

rlhe usual method employed in present lotation to bring about the desired effects of selective flotation is the use of depressing or retarding reagents, which, added to a pulp l. containing a complexity of minerals, have the quality of selectively retarding or depressing one or more of these minerals Without interfering With the ree ilotation oi others.

As an example of such selective flotation may be cited the use of potassium cyanide in an alkaline ore pulp containing sulphide of lead, zinc and iron. The addition of these reagents causes a retarding of the flotation of the iron and reine minerals, Without interlering with lthe flotation of the lead sulphide (galeria) thus permitting the production oi a high grade lead concentrate which, essentially ree ci zinc and iron, forms a commercially valuable product. @ther retarding or depressing reagents used for this, or similar purposes, are sodium sulphide, potassium bichromate, sulphurous acid, etc.

By my improved process it has been dis- 20 covered lthat this selective action or the retardation and depression erects mentioned can be realized Without the use orp .such specic reagents as described, or where they are used the selectivity can be materially inten- 95 sitied, thus permitting a substantial reduction in the quantities of such reagents, thereby e'ecting important economies in the application of the process, and at the same time 4 produce enhanced metallurgical results. rl`his peculiar selective edect or action l obtain by subjecting the pulp (prepared in the usual Way) and containing a complexity of minerals to agitation and to the action of a partial vacuum, the intensity of which is controllable and at the same time introducing and Working into the pulp mass a controlled and minimum quantity `of air in a critical amount. Eoth the degree of vacuum and the amount oi air admitted are subject to variation depending on the ore and its constitute minerals.

By applying these principles in a large scale operation l have been 'able to obtain an excellent separation between the lead, zinc and iron minerals in ores generally, and particularly in an ore which had thereto'fore resisted all efforts at a successful separation by the normal methods referred to above.

An example ci the results obtained onthis ore before and after applying my present method Will serve to illustrate the superiority of my present process.

Mill run after subjecting pulp to present Well known methods universally in use a Mill head assayed 5% lead, zinc, 6% iron.

.Lead concentrates assayed 22% lead, 30%

zinc.

No zinc concentrate vvas produced.

Flotation reagents used were for lead Xanthate: 0.10 lbs. per ton.

Pine oil: 0.10 lbs. per ton.

Lime: l to 8 lbs. porton.

Cyanide: 0.7 5 to 3 lbs. per ton.

No separation was edected.

Mill run after subjecting pulp to vacuum method ll/lill heads, assayed 5% lead, 7% Zinc, 6% iron.

Lead concentrates, assayed 65% lead, 5% zinc, 3% iron.

Zinc concentrates, assayed 2% lead, 55% zinc, 1% iron.

Flotaticn reagents used were 'or lead Xanthate: '0.,l0 lbs. per ton.

Pine oil: 0.3.0 lbs. per ton.

Lime: 0.5 to 0.15 lbs. per ton.

Cyanide: 0.05 to 0.10 lbs. per ton.

Flotation reagents used for zinc "averci- Xanthate: 0.15 lbs. per ton.v

Copper sulphate: 0.25 lbs. per ton.

An excellent separation and high` grade lead and zinc products Were obtained.

The preferred apparatus necessary to carry out my method, that is, to apply a controllable vacuum to the pulp mass simultaneously vvith a controlled admission of a quantity of air into said pulp mass, While the mass 1s in agitation is preferably constructed in the lli following manner, reference being had to the accompanyingl drawings, wherein Figure 1 is aitransverse, vertical, sectional view of the preferred embodiment.

Figure 2-is a transverse, horizontal, sectional view on"line 2-2 of Figure 1.

Figure 3 is a horizontal sectional view on line 3-3 of Figure 1.

The preferred form of construction, as illustrated in the drawings, comprises a sub; stantially rectangular chamber 10, consisting of upper side and end wall sections 11, 12, 13 and 14, the lower portions 15, 16, 17 and 18 of the sections inclining towards the center of the chamber 10, and a bottom wall 19, mounted upon a suitable supporting frame work. Communicating with the bottom of the chamber 10 is an inlet pipe 20 through which the pulp to be treated is introduced into the apparatus, the pipe 20 passing through the inclined portion 15 of wall section 11 and discharging into the chamber near the bottom open end 22 of a vertically disposed truncated conical shell or casing 23, suspended in the chamber 10 by the frame work 23. The upper portion of casing 23 terminates adjacent the upper edges of side walls 13 and 14 of chamber 10.

Disposed in casing 23 and rigidly secured to the lower portion of a vertically disposed shaft 26, is a hollow truncated cone 27, similar in configuration to the casing 23. Cone 27 is provided at its lower end with a sleeve 28 to which the shaft 26 is rigidly secured and at its upper end it is provided with a frame 29'having a centrally disposed opening through which the shaft 26 passes. The upper end of shaft 26 passes through the bearing 31 secured to a cross beam 32 of the supporting frame work, and on the upper ond is secured a pulley 33, driven by a motor 33 through a belt connection.

IThe peripheral wall of rotating cone 27 is longitudinally slotted at 40 to permit air to be drawn therethrough to the 'space formed between shell 23 and rotor 27 during the operation of the apparatus.

The surface of the cone 27 is provided with a plurality of helical ribs 34 pulp flow in the interspace 34 shell 23 and cone 27.

Upwardly from the frame 29 extends an annular iage 41` having a running it with a complementary fiange 42 depending from the under-surface of a hood .43, carried by bearing sleeve 31. The peripheral edge 44 of the hood 43 depends into the chamber 10 to a point below the upper edge of the shell 23, and also below the upper edge of the outlet 45 controlled by a gate 46. The hood 43 forms a substantially air tight chamber 47, over the interspace between the shell 23 and cone 27, the chamber being sealed by the pulp level in the chamber'lO. Complementary flanges 41 and 42 provide a chamber 48 assisting the between the at the upper end of the cone 27. An air inlet valve 49 is carried by'the hood 43 fand is manually controllable to admit air into .the cone 27 and chamber 48, and a similar valve 50 is provided to control the admission of air into chamber 47. Suitable ribs or iins 51 are carried on the inner surface of the skirt 44 of the hood 43 to prevent any swirling tendency of the pulp discharged into the chamber 47 by the action of cone 27 In operation, the pulp enters the conical interspace 34 between the cone 27 and shell 23. In this space the action of the helices 34 rapidly elevates the pulp to be forcibly eX- panded, thereby causing` the formation of a partial vacuum in the pulp mass. The quantity of air which may be drawn into the pulp is controlled by valve 48 which permits a very fine adjustment of the air inlet to the interihr of the rotating cone 27 This valve controls both the quantity of air admitted and the degree of vacuum maintained in the rising column of the expanding pulp mass. Independent of this, the vacuum in chamber 47 is regulated by means of valve 50. 'lhe pulp on leaving the conical interspace 34 enters chamber 47 where the pulp is brought to rest, being prevented from assuming a rotating action by projecting ribs 51, provided on the walls of said chamber for this purose.

p It must be noted that in operation, the pulp level in chamber 47 rises above the level ofthe tank, the height depending on the degree of vacuum maintained and controlled by valve 50.

It will thus be apparent that in carrying out my method invention, I maintain the ore pulp either with or without a reagent added thereto. in a continuously moving body. and maintain the continuously moving body in vacuum by controlling the air admitted thereinto, and it is preferable that this continuously moving body be drawn' from the main pulp body and again discharged thereonto, the froth floating therefrom.

I claim :-l

1. The method in the fiotation process of floating selectively one or more minerals contained in ore pulp, which consists in subjecting a moving column of air-impregnated ore pulp to the action of a vacuum and propor tioning the degree of vacuum and air entry into the pulp to selectively fioat one or more minerals from one or more other normally floatable minerals.

2. The method in the iiotation process of fioating selectively one or more minerals contained in ore pulp, which consists in inducing a iiow of ore pulp along a defined path while introducing air thereinto and creating a vacuum within the ore pulp during said course of ow, and proportioning the degree of vacuum and air entry into the pulp to selectively iioat one or more minerals from one. or more other normally oatable minerals.

3. The method in the flotation process'of floating selectively one or more minerals in ore pulp, which consists in inducing an agglomerate of ore pulp to iow in a continuous path, admitting air into said pulp and subjecting said pulp to interstitial vacuum produced therein by progressively increasing the cubic displacement of said agglomerate during an agitation thereof in the course of said iow, the degree of vacuum and air entry into the pulp being proportioned to selectively float one or more minerals from one or more other normally floatable minerals.

4E. The method in the flotation process of iloating selectively one or more minerals from one or more other normally loatable minerals contained in ore pulp, which consists in forming the pulp with its'contained ores in a rising expanding column while admitting air thereinto in controlled quantities, and maintaining the rising expanding column in a degree of vacuum proportioned to the admitted air, the degree of vacuumibeing proportioned to selectively ioat oe or more minerals from one lor more other normally floatable minerals.

5. The method in the flotation process of oating selectively one or more minerals from one or more other normally iioatable min-` erals contained in ore pulp, Whichconsists in forming the pulp with its contained ores in a rising hollowcolumn, increasing in diameter as it rises, introducing to said pulp controlled quantities of air, and maintaining therising hollow column in a degree of vacuum, the degree of vacuum being proportioned to selectively float one or more minerals from one or more other normally floatable minerals.

6. The method in the flotation process of floating selectively one or more minerals from one or more other normally oatable minerals contained in ore pulp, which consists in con tinuously lifting from the main pulp body a rising column of the pulp containing ores', introducing into the pulp controlled quantities of air, maintaining the rising hollow column in a degree of vacuum proportioned to the quantity of air admitted to selectively ioat one or more minerals from one or more other normally floatable minerals, and dischzrging the column on to the main pulp bo 7 .yThe method in the otation process of ioating selectively one or more minerals from one or more other oatable minerals contained in ore pulp, which consists in continuously removing Jfrom the main pulp body an expanding column of ore pulp, while' admitting a partial air thereinto, maintaining the column in a partial vacuum, proportionone or more minerals from one or more other normally loatable minerals.

8. The method in the flotation process of floating selectively one or more minerals contained in ore pulp, which consists in forming the pulp with its contained ores in a continuously moving column, and maintaining the moving column in a partial vacuum, and proportioning the degree of vacuum to selectively float one or more minerals from one or more other normally floatable minerals.

9. The method in the flotation process of floating selectively one or more minerals from oneor more other normally iioatable minerals in ore pulp, which consists in inducing an agglomerate of ore pulp to iow in a continuous path and subjecting said ore pulp to interstitial vacuum produced therein by forced expansion of the pulp agglomerate during said course o f How, and proportioning the degree of vacuum to selectlvely oat one or more minerals from one or more other normally floatable minerals.

In testimony whereof I have signed my name to this specication.

MAX KRAUT.

ing the degree of vacuum to selectively float 

